Honing tool with renewable tool holder slot



Nov. 20, 1962 A. S. CZUBAK HONING TOOL WITH RENEWABLE TOOL HOLDER SLOT Filed June 1. 1959 INVENTOR. #22177 6'. C2 all? 3,%4,597 Fatented Nov. 20, 1952 line 3,964,397 HGNENG T081 WITH RENEWABLL, T 591.

. HGLDER SLGT Albin S. Czuhak, Detroit, Mich, assignor to- Micrornatic Hone Corporation, Detroit, Mich a corporation of Michigan Filed June 1, 1959, Ser. No. 817,376 1 Claim. (Cl. 5ll84.3)

This invention relates to honing tools and particularly to a honing tool having improved stone supporting means.

The honing tool of the present invention is of the type utilized in the finishing of cylindrical surfaces, such as cylindrical bores. Such honing tools generally include a metal body having a plurality of radially adjustable abrasive stones spaced circumferentially about the periphery thereof. Examples of such honing tools previously known may be found in United States Patents los. 2,315,062 and 2,383,657, both assigned to the assignee of the present invention. It has heretofore been the practice to form the honing tool body with a plurality of radial tools which are open to the outer periphery of the body and in which the honing stones are supported. During the honing operation, the honing stones are advanced radially outwardly to compensate for the material abraded from the working face thereof and to increase the diameter of the work bore. Thus, sufficient clearance had to be allowed between the opposite lateral walls defining the slot to permit the honing stone to be smoothly slidable therein. During the honing operation, the honing tools is unidirectionally rotated and is also reciprocated to evenly hone all locations on the work surface. As a result of such movement of the honing tool relative to the work surface, the individual abrasive stones are subjected to substantial dynamic forces. Such forces can rapidly change and considerable shock can be imparted to the honing tool with the periodic build-up and break-away of grit and abrasive on the working surface of the stones. in addition, those surfaces of the tool body which define the trailing or load-bearing lateral walls of the stone slots are subject to considerable wear and abrasion from the random abrasive materials which work into contact therewith. Over a period of time, this abrasion and wear can become so marked that the slots fail to retain the abrasive stones in a proper manner. When such a condition develops, it has heretofore been necessary to replace the enti e body portion of the honing tool, which is a relatively expensive part. It is, therefore, an object of the present invention to provide a honing tool having means by which the stone slot-defining portions of the hone body may be inexpensively and conveniently restored to a size and shape in which they will properly retain and support the stones.

It is another object of the present invention to provide a honing tool having means for reinforcing and backing the abrasive stones in a manner reducing the incidence of damage to the honing stones as a result of shock and dynamic forces encountered in the honing operation, thereby prolonging the life of the stones.

It is a further object of the present invention to provide a honing tool of the above character having means for limiting the inequality of wear between the several stones of a honing tool in the event of variations in the structure or hardness between said stones.

It is still another object of the present invention to provide a honing tool of the above character which is not only inexpensive of manufacture, but which may also be inexpensively maintained.

It is still another object of the present invention to provide a honing tool of the above character which is of sturdy construction and possesses a long, useful life.

These and other objects of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings wherein:

FlGURE 1 is a view, partly in section and partly in elevation of a honing tool embodying the principles of the present invention;

PEG. 2 is a sectional view of the structure illustrated in FIG. 1 taken along the line 2-2 thereof;

FIG. 3 is an exploded perspective view of a portion of the structure illustrated in FIGS 1 and 2; and

HQ. 4 is a view of structure similarly illustrated in FIG. 3 showing another form of the present invention.

Referring now to the drawings, FIGURE 1 illustrates a honing tool 11 having a generally spool-shaped body portion 13 provided with a central axial bore 15 and a generally cylindrical outer periphery 17. The body portion 13 is integrally connected to a drive shaft 19 which is shown in FIG. 1 as being coaxially fastened to a fragmentarily illustrated honing machine spindle 21. The body portion 13 is thus adapted to be rotated about the axis of its bore by rotation of the spindle 21 of the honing machine with which it is used. The body portion 13 carries a plurality of radially adjustable abrasive elements or stones 23 spaced circumferentially therearound and having their working faces 25 disposed radially outwardly of the periphery 17 of the body. A double cone wedge element 27 is disposed within the bore 15 of the body and is adapted to be moved in an axial direction by an actuating rod 29 connected to the upper end thereof and extending upwardly through the machine spindle 21. inwardly and downwardly tapered conical surfaces 27a and 27b of the wedge element 27 contact the inclined inner ends of a plurality of intermediate expansion members 31 corresponding in number to the abrasive elements 23. Each of the expansion members 31 is in abutting relationship with one of the abrasive elements 23 and serves to transform axial downward movement of the wedge element 27 into radially outward movement of the abrasive elements 23. Upon upward movement of the wedge element 27, the abrasive elements 23 are retracted by means of conventional garter springs 32 which also serve to maintain the abrasive elements 23 in assembly with the body member 13. Both the intermediate expansion members 31 and the abrasive elements 23 are disposed within axially elongated slots 33 formed in the body 13 and extending from the bore 15 axially outwardly to the outer periphery 17 of the body. The radially inner portions 35 of the slots 33 are relatively narrow, being of only sufiicient width to slidably but snugly accommodate the intermediate expansion members 31. However, the radially outer portion 37 of the slots 33 is of substantial width to accommodate not only an abrasive element 23 but also a supporting member r wear strip 39. The backing members 39 are detachably secured to the body 13 by suitable fastening means, such as screws 4-1, extending through apertures 43 formed in the backing members 39 and threaded into the body portion 13. The backing members 39 are positioned so that the abrasive elements are snugly but slidably confined between a shoulder 45 defining one side wall of the slot 33 and a flat side 47 of the backing member 39 disposed parallel to the shoulder 45. Both the shoulder 45 and the side 47 are parallel to the axis of rotation of the tool and are disposed generally normal to the direction of rotation of the tool at the adjacent periphery thereof. The tool is designed to be rotated in a direction so that each backing member 39 will be on the following or trailing side 48 of its associated abrasive element 23 and will receive the torsional load imparted to the honing tool by the movement of the working faces 25 of the abrasive elements 23 across the work surface.

Each of the abrasive element 23 includes a bonded abrasive body 49 enclosed within a casing 51 of plastic which covers all but the working face 25 of the abrasive body 49. As may be best seen-in FIG. 2, the plastic casing 51 is formed with a laterally projecting lug 53 adjacent the inner margin of its trailing side 48 and which is received within a conformably shaped recess or slot 55 formed in the side 47 of the backing member 39. The

engagement of the lug 53 in the slot 55 prevents axial movement of the abrasive element 23 relative to the body upon the reciprocation of the honing tool. However; the lug 53 is free to slide within the slot 55 upon radial adjustment of the abrasive elements 23. The plastic casing 51 wears away with the abrasive body 49 adjacent the working face 25 thereof and presents no interference with the honing operation.

FIG. 4 illustrates another form of the invention in which an abrasive element 61 is provided with a laterally extending lug 63 on the leading side thereof adapted to fit Within a conformably shaped recess (not shown) in the tool body. In this form of the invention, the lug 63 is on the leading side of the abrasive element 61 and a backing member or wear strip 65 supportingly abuts the abrasive element 61 on its trailing side.

In practice, the external diameter of the honing tool across an opposite pair of supporting members or guide strips 39 is provided to be slightly less than the diameter of the unhoned bore of the workpiece which the tool is to enter. Before entry of the tool into the workpiece, the abrasive elements 25 are retracted by upward movement of the wedge element 27 so that the working faces 25 of the abrasive elements 23 are disposed radially inwardly of the outer periphery of the supporting members 39. Thus, the backing members 39 serve to guide the tool in its entry into the bore and prevent the edge of the bore from striking the working faces 25 of the abrasive elements 23 and possibly breaking them. Once the honing operation has begun and the abrasive elements are advanced into abrading engagement with the workpiece, it occasionally occurs that one or more abrasive elements will wear more rapidly than the others, due to structural differences between the bonded grit body portions 49 of the elements 23. Under such circumstances, the tool tends to gyrate slightly in an eccentric manner. The presence of the wear strips or backing members 39 adjacent such rapidly Wearing abrasive elements 23 serves to limit the amount of this eccentric wear, inasmuch as the working faces 25 cannot wear beyond the outer periphery of the backing members 39 and such backing members 39 will support a substantial portion of the pressure produced by the diametrically opposite abrasive elements.

While the backing members 39 may be manufactured from a variety of materials, it has been found that materials having a moderate amount of elasticity or deflectability will materially contribute to the ability of the abrasive elements to withstand shock and other dynamic forces without breakage. Nylon has proven quite suitable for this purpose. However, vulcanized fiber, Bakelite and other organic materials or nonferrous bearing materials, such as brass, have also been found to be suitable Carboloy has also been used and has been found to possess a high resistance to wear, but it has been found to-produce scoring of certain work surfaces. Vulcanized or bonded fiber possesses excellent shock-absorbing characteristics, low cost and is sufficiently soft as not to score the surface of almost any workpiece. However, it tends to wear at a somewhat greater rate than ot m ri ls.-

It will be appreciated that, inasmuch as the surface supporting the trailing side of the abrasive elements receives the load of the honing stones resulting from the frictional resistance of the abrasive elements to movement across the work surface upon rotation of the tool, the surfaces abutting the trailing sides of the honing stones will be subjected to far greater wear than any other slotdefining surfaces. The magnitude of wear is considerably increased by particles of grit or abrasive which work their way betwen the abrasive elements and such surfaces and produce an abrasive action on the trailing side wall of the slot. In honing tools heretofore known, it has been necessary to discard and replace the body of the tool after a period of time when the slots became so enlarged as to inadequately support the stones. It will be readily apparcut that in the honing tool of the present invention, the backing elements 39 may be easily removed from the hone body by loosening of the screws 41 and new supporting elements installed. Inasmuch as the backing elements 39 may be molded or otherwise inexpensively manufactured from inexpensive materials, such replacement may be made and the stone slots restored to a like new condition at a substantial savings of cost over replacement of the honing tool body, which is a relatively complicated and expensive precision-machined steel part.

While it will be apparent that the preferred embodiments herein illustrated are well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claim.

What is claimed is:

'In a honing tool, a body member adapted to be rotated, said body member having a plurality of angularly spaced radially extending outwardly open slots, a radially adjustable honing element disposed in each of said slots, each of said honing elements having a length of abrasive material provided with a working face at the radially outer periphery thereof, a non-abrasive combination wear and guide member separate from said abrasive member disposed in each of said slots so as to be slidably engaged by said honing element on one side thereof, said combination wear and guide members being of a width in a circumferential direction substantially equal to the width of the abrasive material of said honing elements and having radially outer periphery disposed closely adjacent to the working face of said abrasive material whereby said combination wear and guide members are operable to absorb the torque from said honing stones during the honing opera tion and are operable to stabilize the tool by engagement with the wall of the bore being honed in the event of excessive wear of the abrasive material of the honing element adjacent thereto, and a threaded fastener extending through each of said combination wear and guide members in a direction substantially parallel to the direction of adjustment of the adjacent one of said honing elements for detachably securing said combination wear and guide members to said body member.

References Cited in the file of this patent UNITED STATES PATENTS 1,673,924 Snyder June 19, 1928 2,330,184 Hause Sept. 21, 1943 2,421,470 Sunne June 3, 1947 2,675,654 Harris Apr. 20, 1954; 

